Morphological characterization and response of red flower rag leaf (Crassocephalum crepidioides Benth S. Moore) to organic and inorganic fertilizers and arbuscular mycorrhizal fungus

Red flower rag leaf (Crassocephalum crepidioides) is one of the underutilized vegetables consumed globally. Pot trials were conducted to characterize 15 morphologically distinct accessions of C. crepidioides and assess the effects of treatment combinations of eggshell, NPK 15:15:15, poultry manure and arbuscular mycorrhizal fungus(Glomus mosseae) as soil amendments on growth and yield-related characters of C. crepidioides. Thereafter, 48 seedlings of the best performing accession were transplanted into perforated polythene bags filled with 7 kg of heat-sterilized soil. The experiment was laid out in a completely randomized design with three replicates. Treatment combinations were incorporated into in the polythene bags 1 week after transplanting, while control plants received no amendments. The results showed that accession NH/GKB-15 had the highest plant height (29.83 cm), stem length (27.67 cm), number of leaves (15) and length of internode at node 3 (1.13 cm) and node 4 (1.17 cm). The growth and yield characters of this best performing accession (NH/GKB-15) in response to soil amendments showed that poultry manure produced the tallest plants (55.17 cm), longest and widest stems (48.35 and 0.66 cm), longest and widest leaves (16.39 and 6.26 cm, respectively), and higher number of inflorescence (2.13). With NPK 15:15:15 the seedlings did not survive. Poultry manure should therefore be utilized for better plant nutrition and faster growth of C. crepidioides seedlings as well as for safer consumption of the leafy vegetable.

Arbuscular Mycorrhizal Fungus Alters Root System Architecture in Camellia sinensis L. as Revealed by RNA-Seq Analysis

Arbuscular mycorrhizal fungus (AMF), forming symbiosis with most terrestrial plants, strongly modulates root system architecture (RSA), which is the main characteristic of root in soil, to improve plant growth and development. So far, the studies of AMF on tea plant seedlings are few and the relevant molecular mechanism is not deciphered. In this study, the 6-month-old cutting seedlings of tea plant cultivar “Wancha No.4” were inoculated with an AMF isolate, Rhizophagus intraradices BGC JX04B and harvested after 6 months of growth. The indexes of RSA and sugar contents in root were determined. The transcriptome data in root tips of mycorrhizal and non-mycorrhizal cutting seedlings were obtained by RNA-sequence (Seq) analysis. The results showed that AMF significantly decreased plant growth, but increased the sucrose content in root and the higher classes of lateral root (LR) formation (third and fourth LR). We identified 2047 differentially expressed genes (DEGs) based on the transcriptome data, and DEGs involved in metabolisms of phosphorus (42 DEGs), sugar (39), lipid (67), and plant hormones (39) were excavated out. Variation partitioning analysis showed all these four categories modulated the RSA. In phosphorus (P) metabolism, the phosphate transport and release (DEGs related to purple acid phosphatase) were promoted by AMF inoculation, while DEGs of sugar transport protein in sugar metabolism were downregulated. Lipid metabolism might not be responsible for root branching but for AMF propagation. With respect to phytohormones, DEGs of auxin (13), ethylene (14), and abscisic acid (5) were extensively affected by AMF inoculation, especially for auxin and ethylene. The further partial least squares structural equation modeling analysis indicated that pathways of P metabolism and auxin, as well as the direct way of AMF inoculation, were of the most important in AMF promoting root branching, while ethylene performed a negative role. Overall, our data revealed the alterations of genome-wide gene expression in tea plant roots after inoculation with AMF and provided a molecular basis for the regulatory mechanism of RSA (mainly root branching) changes induced by AMF.